kdb: kdb_current_regs should be private

As of the patch ("MIPS: kdb: Remove old workaround for backtracing on
other CPUs") there is no reason for kdb_current_regs to be in the
public "kdb.h".  Let's move it next to kdb_current_task.
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Link: https://lore.kernel.org/r/20191109111623.2.Iadbfb484e90b557cc4b5ac9890bfca732cd99d77@changeidSigned-off-by: Daniel Thompson <daniel.thompson@linaro.org>

include/linux/kdb.h

@@ -183,8 +183,6 @@ int kdb_process_cpu(const struct task_struct *p)
 	return cpu;
 }
 
-/* kdb access to register set for stack dumping */
-extern struct pt_regs *kdb_current_regs;
 #ifdef CONFIG_KALLSYMS
 extern const char *kdb_walk_kallsyms(loff_t *pos);
 #else /* ! CONFIG_KALLSYMS */

kernel/debug/kdb/kdb_private.h

@@ -242,6 +242,7 @@ extern void debug_kusage(void);
 
 extern void kdb_set_current_task(struct task_struct *);
 extern struct task_struct *kdb_current_task;
+extern struct pt_regs *kdb_current_regs;
 
 #ifdef CONFIG_KDB_KEYBOARD
 extern void kdb_kbd_cleanup_state(void);